Tooth surfaces are constantly experiencing a loss and gain of minerals. This process is partially kept in balance by the chemical composition of saliva and extra-cellular fluid. Disruption of the tooth surface integrity can occur by acidic food and beverages, bacterial challenge and erosion by exaggerated tooth brushing or grinding of the teeth. These processes are accompanied by a demineralization of the exposed tooth surfaces leading to clinical conditions such as dentine hypersensitivity.
Dentine hypersensitivity, also called tooth sensitivity, is a temporary induced pain sensation produced when hypersensitive teeth are subjected to changes in temperature and/or pressure or to chemical action. Hypersensitivity may occur when the dentin of a tooth is exposed due to, for example, demineralization. Dentine generally contains channels, called tubules, that allow material and energy transport between the exterior of the dentin and the interior of the tooth where the nerve is located. Exposure of these tubules to external stimuli can cause irritation of the nerve and lead to the discomfort or pain of hypersensitivity.
Many attempts have been made to control dentine hypersensitivity. One approach is to reduce the excitability of the nerve in a sensitive tooth by altering the chemical environment of the nerve to make the nerve less sensitive. Some “nerve agents” or “nerve desensitizing agents”, such as potassium nitrate, are generally used for this purpose. Another approach is to fully or partially block or occlude the tubules so as to prevent or limit exposure of the nerve to external stimuli. The agents for this purpose are referred to as “tubule blocking agents”. Charged polystyrene beads, polyacrylic acid, apatite, and some polyelectrolytes have been reported as tubule blocking agents.
Despite these attempts, there continues to be a need for effectively controlling dentine hypersensitivity. There continues to be a need for reducing dentine hypersensitivity. There continues to be a need for preventing dentine hypersensitivity. There continues to be a need for a long-lasting efficacy in controlling dentine hypersensitivity.